The present invention relates to a hydraulically operated swash-plate apparatus such as a hydraulically operated continuously variable transmission including a hydraulic pump and a hydraulic motor which ar interconnected by a closed hydraulic circuit, and more particularly to a shoe structure in such a hydraulically operated swash-type apparatus.
There have been known hydraulically operated swash-type apparatus such as hydraulically operated swash-plate apparatus including a cylinder block rotatably supported in a case and having a plurality of axial cylinders arranged in an annular pattern, plungers receive respectively in the cylinders, a swash plate supported in the case and slidably held against the free ends of tee plungers, and an actuator for tilting the swash plate, the stroke by which the plungers can move into and out of the respective cylinders being variable according to the angle of inclination of the swash plate. One known such arrangement is disclosed in Japanese Laid-Open Patent Publication No. 55-27556.
When the known hydraulically operated swash-plate apparatus is operated as either a pump or a motor, a thrust force acts between the free ends of the plungers and the swash plate. The swash plate and the cylinder block are supported by different case members. Since the case is subject to a relatively large tension during operation, the structure of the case must be mechanically strong enough to withstand such a tension. The case is generally made of cast iron or aluminum, and is of a large thickness in order to withstand the tension it suffers. As a result, the apparatus is large in size and heavy.